PM8621 PMC-Sierra, Inc., PM8621 Datasheet - Page 145

• Manufacturer Part Number: PM8621
• Description: NSE-8G Standard Product Data Sheet Preliminary
• Manufacturer: PMC-Sierra, Inc.

12.6
12.6.1
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2010850, Issue 1
If some links are switching DS0 traffic (“1 in 48” frame mode) and some are not (“1 in 4” frame
mode), the input RC1FP and the qualifying signal from the DCB (from mf_swap), will be running
at “1 in 48” frame mode. The links in “1 in 48” frame mode should use the unexpected interrupt
while the others should use the missing interrupt.
If a link no longer has any C1 activity, the firmware should assume the link has lost alignment,
and should force R8TD OCA for the port.
These instructions assume the PMC NSE-8G Device driver is not being used. If the supplied
driver is being used, this will all be handled within that driver.
DS0 Cross-Bar Switch (DCB) Operation
While the DCB is the Space Switch central to the NSE-8G it also contains the DCB C1 Delay
Register. This register must be programmed with the delay (in 77.76 MHz clock cycles) between
RC1FP (RC1DLY) and the expected arrival time in the R8TD SIPO of the C1 character. This
value is expected to be in the order of 51 clock cycles + 9720 or +1080 for SBI mode or
TeleCombus mode respectively. The 51 value is approximate and very dependant on the system
architecture and transmission line lengths between the SBS and NSE-8G components. This must
be obtained empirically by the system designer during product commissioning.
Figure 25 Architecture of the RAM Input Interface
In port transfer mode, the microprocessor updates only one configuration entry within a word of
offline connection memory page. The steps to perform a port transfer are shown in the following
example:
Configuring the DCB using Port Transfer Mode
oncfg[159:0]
offcfg[159:0]
160
5
160
B
5
160
160
. .
.
F
C
30
160
NSE-8G™ Standard Product Data Sheet
E
D
30
160
CFGO[29:0]
pgNdin[159:0]
Preliminary
144